1. Field of Invention
The invention relates to a display device and a display method for a vehicle which are used to display an image in the field of view of a driver of the vehicle.
2. Description of Related Art
In a conventional vehicle head-up display (HUD) as a vehicle display device, which displays images by projecting light emitted from a display portion in front of a vehicle driver, to provide the driver with various kinds of information. In a conventional HUD, the position of a displayed image must be adjusted to allow a driver to view the displayed image, because the position of the eyes of a driver may vary according to the driver's physical constitution, posture, etc.
Japanese Patent Application Publication No. 2008-151992 (JP-A-2008-151992) describes an example of a conventional head-up display. According to JP-A-2008-151992, the HUD device displays images in the driver's field of view by using a concave mirror that reflects the image projected from display means. In addition, the display device uses a camera to detect the position of the driver's eyes relative to the vehicle, and adjusts the angle of the concave mirror based on the detected position of the eyes so that the image is displayed at a position that allows the driver to appropriately view the displayed image.
However, in the HUD device described in Japanese Patent Application Publication No. 2008-151992 (JP-A-2008-151992), the display position is adjusted according to changes in the position of the driver's eyes even when the driver is not looking at the displayed image, for example, when the vehicle is stopped. Therefore, the constant adjustment of the image display position meets the position of the driver's eyes more than necessary, may annoy the driver. In addition, because detection of the position of the driver's eyes and adjustment of the angle of the concave mirror continue even when the driver is not viewing the displayed image, the display position is sometimes needlessly adjusted.